Updating support for instance based network descriptions. Preferred format for NML2 is shown in examples/NML2_InstanceBasedNetwork.nml, with lists of instances in populations, connections in projections and inputs in inputLists.
jLEMS can now read and execute nml files in this format, see NeuroML2CoreTypes/LEMS_NML2_Ex13_Instances.xml.
Schema and other examples updated accordingly.
Note: paths used in selecting cells in connection and input need to be improved!